Molecular evidence of bovine herpesvirus 1 and 5 in cattle with suspected rabies in Rio Grande do Sul state, Brazil.

Rabies and herpetic encephalitis are the main viral infections in bovines with neurological symptoms. Bovine rabies has a high prevalence in Central and South America, while bovine encephalitis associated with herpesvirus is especially important in South America. Viral isolation is the classical way to confirm herpesvirus infection, but molecular evidence of the presence of the virus in affected animals is gaining importance in the diagnosis of the disease in the laboratory. This study investigated the presence of herpesvirus type 1 and 5 (BoHV-1 and BoHV-5) in 182 encephalon of rabies-suspected cattle in Rio Grande do Sul state (RS), Brazil using multiplex real-time polymerase chain reaction (mRT-PCR). The rabies virus was investigated by direct fluorescent antibody assay and intracerebral suckling mouse inoculation. The genomes of BoHV-1 and BoHV-5 were detected in 17% of samples. BoHV-5 and BoHV-1 were detected in 100% and 19% of BoHV positive samples, respectively, indicating the circulation of the pathogens in cattle herds in RS. The high Ct values and the absence of isolation suggest viral latency. Coinfection of herpesvirus and the rabies virus was detected in 28% of samples, although no significant association between pathogens was observed. Rabies was detected in 57.7% of suspected samples, confirming the importance of the disease in the state. Concerning the method by which samples were conserved, no significant difference was observed between the number of positive results in frozen and refrigerated samples.

Genotoxic effect and rat hepatocyte death occurred after oxidative stress induction and antioxidant gene downregulation caused by long term fluoride exposure.

Studies focusing on possible genotoxic effects of excess fluoride are contradictory and inconclusive. Currently, studies have reported a probable link to oxidative stress, DNA damage and apoptosis induced by fluoride in rat hepatocytes. We developed an in vivo study administering three doses of fluoride by gavage given to rats for 60 day. Micronucleus test was applied to investigate genotoxic potential of fluoride. The TUNEL method determined DNA fragmentation and apoptosis. Biochemical parameters to investigate mitochondrial swelling and oxidative stress. Semi-quantitative RT-PCR and immunostaining to determine mRNA and protein expression of antioxidant enzymes. Analyses of the hepatic function and morphology were performed. Our results revealed the genotoxic potential of fluoride but did not confirm mitochondrial swelling nor an increase of positive TUNEL labelling induced by fluoride, indicating absence of apoptosis. Oxidative stress induction was confirmed and is probably associated to DNA damage. Cell death events such as empty nuclear spaces, cytoplasm degeneration, nuclear pyknosis, karyorrhexis and karyorrhexis followed by karyolysis were observed. Hepatic function did not appear to be significantly modified makes no evidence of necrosis and suggesting other cell death pathway, the autophagic. In conclusion, prolonged fluoride intake at chosen concentrations caused imbalance of the cellular oxidative state, affected DNA and disrupted cellular homeostasis. It is recommended that fluoride supplementation requires a fresh consideration in light of the current study.

Herd-level risk factors for bovine viral diarrhea virus infection in dairy herds from Southern Brazil.

A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 300 randomly selected dairy herds which were tested for antibodies in bulk tank milk (BTM) using a commercial indirect ELISA kit (SVANOVA). Results from the analysis were interpreted according to the Swedish BVDV control scheme. The testing revealed 129 (43%) BTM BVDV antibody-positive herds. Use of artificial insemination (AI) and herd size were significantly associated with BVDV serological status (P<0.05). Dairy herds that use AI had 2.82 increased odds of BVDV-seropositivity (95% CI: 1.02-7.24). Since the semen used in the studied population come from known selected sires, it was hypothesized that AI technicians should represent an important risk factor because the increasing number of visitors in the farm can introduce the virus through the clothes, shoes and contaminated equipment.

Responses of broiler chickens to cottonseed- and soybean meal-based diets at several protein levels.

Three experiments were conducted to evaluate the performance of broiler chicks fed diets with cottonseed meal (CSM) as the major protein source. Experiment 1 was a 3 x 2 factorial with three crude protein levels (17, 20, and 23%) by two protein sources, CSM or soybean meal (SBM). Diets were fed to male broilers (n = 840) in floor pens from 21 to 49 d of age. L-Lysine-HCl was added to keep lysine at 5.22% of protein. Protein source and level had significant (P < 0.001) effects on BW gain (BWG) and feed conversion ratio (FCR), respectively (no source by level interactions). The average BWG were 1.80, 2.00, and 2.00 kg for birds fed CSM-based diets, compared with 1.93, 2.09, and 2.21 for SBM-based diets (17, 20, and 23% protein, respectively). The average FCR were 2.56, 2.31, and 2.25 for CSM-fed broilers and 2.39, 2.16, and 2.08 for SBM-fed broilers. Significant effects of protein source or level were found for percentage of chilled carcass, fillets, tenders, saddles, and fat pads. In Experiment 2, male broiler chicks (n = 336) were used to determine the lysine requirement of chicks fed a corn and CSM-based diet with 20% CSM and 6% SBM. The basal diet contained by calculation 3,200 kcal/kg of ME, 20% CP, and 0.81% lysine. Graded levels of lysine (0.81 to 1.30% in increments of 0.07%) were fed to chicks from 10 to 20 d, and BW and residual feed were measured at 20 d. The requirement, as determined by breakpoint analysis, was 1.023+/-0.01% lysine (R2 = 0.84) for BWG and 1.028+/-0.02% lysine (R2 = 0.56) for FCR. In Experiment 3, a 2 x 2 x 4 factorial arrangement of treatments involved feeding CSM or SBM to male and female broiler chicks (n = 768) from 21 to 42 d at four dietary protein levels (17, 20, 23, and 26% CP). Lysine was kept at 5.5% of the dietary protein and consisted of the calculated minimum level, established in Experiment 2, plus 7%. Protein level, but not source, had a significant effect on BWG and FCR (P < 0.01 and P < 0.001, respectively) for males. The average BWG were 1.53, 1.74, 1.78, and 1.81 kg for birds fed CSM compared to 1.46, 1.72, 1.84, and 1.82 kg for those fed SBM (17, 20, 23, and 26% CP, respectively); average FCR were 2.36, 2.14, 2.05, and 1.97 for CSM compared to 2.35,2.04, 1.87, and 1.80 for SBM. Protein source and level significantly (P < 0.05) affected feed intake. Significant effects of protein source or level were found for percentage carcass, fillet, tenders, leg quarters, and fat pads. Females had similar qualitative responses. This study showed that at slightly higher protein levels CSM could replace SBM in broiler grower diets to achieve similar performance.

Collagenous and elastic system fibres in the aorta of cattle poisoned by Solanum glaucophyllum.

The proportions of fibres of the collagenous and elastic systems were measured in the aortas of three normal heifers and in nine heifers given the calcinogenic plant Solanum glaucophyllum for 15, 30 or 60 days. There were decreases in the amount of collagen relative to reticulin, and in the proportion of elastic fibres which were related to the period of dosing. These changes may have an adverse influence on the animals' cardiovascular function.

Studies on feeding peanut meal as a protein source for broiler chickens.

Four experiments were conducted to compare the performance of broilers fed soybean meal (SBM) versus peanut meal (PNM) as protein sources. Ross x Ross 208 broiler chickens were placed in battery brooders (Experiments 1 to 3, four replicates of 8 chicks per treatment) and floor pens (Experiment 4, four replicates of 34 chicks per treatment). In Experiment 1, addition of 0, 0.1, 0.2, and 0.3% Thr to a corn-PNM-based diet increased 0 to 18 d BW gain (BWG; 0.374c vs. 0.495b vs. 0.508b vs. 0.508b kg, respectively) and decreased feed conversion ratio (FCR; 2.09c vs. 1.63b vs. vs. 1.54b vs. 1.54b g/g, respectively) compared to the corn-SBM-based control diet (BWG = 0.593a and FCR = 1.36a). In Experiment 2, diets were formulated with the same amino acid minimums, and as the percentage of PNM increased in the diets (0, 10, 20, and 32%), BWG decreased (0.560a vs. 0.532a vs. 0.521a vs. 0.458b kg, respectively) and FCR increased (1.72b vs. 1.71b vs. 1.79bc vs. 1.86c g/g, respectively). In Experiment 3, addition of Thr to a corn-PNM-based diet increased BWG (-Thr = 0.284c vs. +Thr = 0.397b kg) and decreased FCR (-Thr = 1.60b vs. +Thr = 1.54b g/g). The BWG and FCR were best for the corn-SBM-based control diet (0.499a kg and 1.38a g/g, respectively). In Experiment 4, during the growing period (18 to 42 d), significant interactions occurred between protein source (PNM vs. SBM) and protein level (16 and 20% vs. 24%) for BW and FCR but not for carcass, breast, or leg quarter yield or fat pad weights (P < 0.05) at 42 d of age. Technical (not economic) performance of birds fed PNM was similar to SBM at the highest protein levels fed. PNM could be used as a protein source for broilers under appropriate economic conditions.

Effects of plant-induced hypervitaminosis D on cutaneous structure, cell differentiation and cell proliferation in cattle.

Solanum glaucophyllum (Sg) (synonym S. malacoxylon) is a plant toxic to cattle due to its high levels of 1,25-dihydroxyvitamin D3 as glycoside derivatives. Sg causes a disease characterized by wasting and calcification of soft tissues. The effects of vitamin D are not only important in calcium homeostasis, but also in immune regulation, cell growth and cell differentiation. Skin samples in Sg-intoxicated and control heifers were studied histologically. Cellular differentiation and proliferation were analysed by immunohistochemical expression of cytokeratins, involucrin and proliferating cell nuclear antigen (PCNA). The results were obtained by image processing and analysis and were statistically evaluated. Sg-intoxicated cattle showed atrophy of epidermis and severe involution of hair follicles and of sebaceous and sweat glands. As judged by PCNA expression, cellular proliferation was reduced, even though the reduction was not statistically significant. The analysed markers of differentiation, e.g. involucrin and cytokeratins 10 and 11, changed in relation to Sg-poisoning. The possible pathogenesis of the skin lesions is discussed.